package com.ddwanglife.juc;

import java.util.concurrent.*;

class MyTask extends RecursiveTask<Integer> {
    private static final Integer ADJUST_VALUE = 10;
    private int begin;
    private int end;
    private int result;

    public MyTask(int begin, int end) {
        this.begin = begin;
        this.end = end;
    }

    @Override
    protected Integer compute() {
        if((end-begin)<=ADJUST_VALUE){
            for (int i = begin; i <= end ; i++) {
                result = result +i;
            }
        }else{
            int middle = (end+begin)/2;
            MyTask task01 = new MyTask(begin,middle);
            MyTask task02 = new MyTask(middle+1,end);
            task01.fork();
            task02.fork();
            result = task01.join()+task02.join();
        }
        return result;
    }
}

public class ForkJoinDemo {
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        MyTask myTask = new MyTask(0,100);
        ForkJoinPool threadPool = new ForkJoinPool();
        ForkJoinTask<Integer> forkJoinTask = threadPool.submit(myTask);
        System.out.println(forkJoinTask.get());
        threadPool.shutdown();
    }
}
